Snowplow and mount assembly

RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 12/246,671 filed Oct. 7, 2008, now U.S. Pat. No. 7,681,334 issued Mar. 23, 2010, which is a divisional of U.S. application Ser. No. 11/231,072 filed Sep. 20, 2005, now U.S. Pat. No. 7,430,821 issued Oct. 7, 2008, which is a continuation of U.S. application Ser. No. 09/878,744 filed Jun. 11, 2001, now U.S. Pat. No. 6,944,978 issued Sep. 20, 2005, all of which are hereby incorporated by reference.

FIELD OF THE INVENTION

This invention relates generally to snow removal equipment and, more particularly, to a snowplow and mount assembly for removably securing a snowplow to a vehicle.

BACKGROUND OF THE INVENTION

It is desirable to provide a snow plow assembly with a mechanism affording attachment to and detachment from a vehicle. The vehicle operator may wish to remove the snow blade during times when the need for plowing snow arises infrequently or when the vehicle is used for purposes other than plowing snow.

To that end the assignee of the present invention obtained U.S. Pat. No. 5,353,530, hereby incorporated by reference herein as if fully set forth in its entirety. That patent discloses a mount frame having arms and a snowplow frame having receivers which receive the arms. The snowplow frame includes a lift frame and an A-frame pivoted to the lift frame. The receivers are formed as a part of the lift frame. The receivers carry latch pins which are spring biased toward a latching position yet which are lockable in an unlatched position. When the arms of the mount frame have been driven into the receivers of the lift frame each of the latch pins are individually released; the bias of the springs drives the pins through holes in the receivers and in the arms thereby latching the lift frame and hence snowplow to the mount frame and hence vehicle. A jack stand is carried by the lift frame and is manually movable to and between an extended ground contacting and snowplow supporting position and a retracted ground noncontacting and snowplow nonsupporting position.

It is desirable to improve upon the invention of U.S. Pat. No. 5,353,530 by providing a snowplow and mount assembly which facilitates more efficient latching of the latch mechanism removably securing the snowplow to the mount and which facilitates more efficient deployment of the jack stand of the snowplow.

SUMMARY OF THE INVENTION

In one aspect the invention is a snowplow and mount assembly comprising a mount frame adapted to be secured to a vehicle, and a snowplow frame. One of the mount frame and the snowplow frame has first and second arms and the other of the mount frame and snowplow frame has first and second receivers, the first and second receivers receiving the first and second arms, respectfully. Respective ones of first and second latch pins removably secure the first and second arms in the first and second receivers. A latch lever is operably associated with the first and second latch pins and simultaneously actuates the latch pins to latched and unlatched positions.

The assembly can further comprise a spring biasing each latch pin into the latched position and a pin extractor associated with each latch pin and actuatable by the latch lever to extract the latch pin from the latch arm against the bias of the spring. The extractor can include a cam which operably cams against the latch pin during the extraction thereof. The latch pin and respective extractor can be mounted in brackets mounted to the snowplow frame, the brackets guiding movement of the latch pin and extractor. The latch pins can travel transversely relative to a longitudinal axis of the assembly and the extractors can travel perpendicularly relative to the travel of the pins. The latch pin can include a cross pin therethrough which can compress the spring against a wall of the bracket as the cam cams against the cross pin. The cam surface can be a ramp.

The latch lever can be pivotally connected to the snowplow frame, and the assembly can further include first and second linkages connected between the latch lever and the extractors. Each of the first and second linkages can include a linkage arm connected to the latch lever, and a linkage rod pivotally connected on a first end to the linkage arm and connected on a second end to the extractor. The latch lever can include a connecting rod extending transversely of the snowplow frame, with the first and second linkages being connected to the connecting rod.

The first and second arms can be part of the mount frame and the first and second receivers can be part of the snowplow frame. The snowplow frame can comprise a lift frame and an A-frame pivotally connected to the lift frame on a rearward end of the A-frame. The assembly can further comprise a plow blade mounted on a forward end of the A-frame.

In another aspect the invention is a snowplow and mount assembly comprising a mount frame adapted to be secured to a vehicle and a snowplow frame including a jack stand movable to and between an extended ground contacting and snowplow frame supporting position and a retracted ground noncontacting and snowplow frame nonsupporting position. A latch mechanism removably secures the snowplow frame to the mount frame. A latch lever actuates the latch mechanism to latched and unlatched positions, the latch lever operably freeing the jack stand for movement into the extended position when the latch mechanism is in the unlatched position and operably preventing jack stand movement maintaining the jack stand in the retracted position when the latch mechanism is in the latched position.

The assembly can further comprise first and second jack stand locks, the first lock preventing relative movement of the jack stand relative to the snowplow frame when the jack stand is in the extended position and the second lock preventing relative movement of the jack stand relative to the snow plow frame when the jack stand is in the retracted position. The first jack stand lock can comprise a jack stand lock lever having an aperture therein through which a leg of the jack stand passes and a spring biasing an edge of the lock lever aperture into contact with the jack stand leg. The spring and lock lever normally prevent upward movement of the jack stand relative to the snowplow frame while permitting downward movement of the jack stand relative to the snowplow frame, whereas pivoting the lock lever against the bias of the spring frees the jack stand leg from the lock lever aperture edge permitting upward movement of the jack stand relative to the snowplow frame.

The second jack stand lock can comprise a jack stand lock pin moveable into and out of an aperture in a leg of the jack stand and a spring biasing the lock pin toward the jack stand leg. The spring and lock pin normally prevent downward movement of the jack stand relative to the snowplow frame, whereas urging the lock pin against the bias of the spring frees the jack stand leg from the pin permitting downward movement of the jack stand relative to the snowplow frame. The jack stand can drop by gravity to the extended position when the jack stand leg is freed from the pin.

The latch lever can include a cam operably connected thereto and the jack stand lock pin can be fixed to a cam follower which cooperates with the cam such that pivoting the latch lever to actuate the latch mechanism to the unlatched position urges the cam follower and hence the jack stand lock pin against the bias of the spring and away from the jack leg and out of the aperture thereof, whereas pivoting the latch lever to actuate the latch mechanism to the latched position permits the spring to bias the jack stand lock pin toward the jack stand leg and into the aperture thereof.

The latch lever can include a connecting rod extending transversely of the snowplow frame, the cam can be a cylinder encircling the connecting rod affixed thereto and the cam follower can be a cylinder encircling the connecting rod and a slidable relative thereto. The cam cylinder and cam follower cylinder can have mating arcuate surfaces.

In further aspects the invention provides methods of attaching a snowplow frame to and detaching a snowplow frame from a mount frame. A method of attaching a snowplow frame to a mount frame comprises providing a mount frame secured to a vehicle and a snowplow frame, one of the mount frame and the snowplow frame having first and second arms and the other of the mount frame and the snowplow frame having first and second receivers, the first and second receivers receiving the first and second arms, respectively, one of the mount frame and the snowplow frame having first and second latch pins, respective ones of which removably secure the first and second arms in the first and second receivers, and a lever operably associated with the first and second latch pins to simultaneously actuate the latch pins to a latched position, effecting relative movement between the mount frame and the snowplow frame so that the receivers receive the arms therein and actuating the lever to simultaneously actuate the pins to the latched position.

A method of detaching a snowplow frame from a mount frame comprises providing a mount frame secured to a vehicle and a snowplow frame removably attached to the mount frame, one of the mount frame and the snowplow frame having first and second arms and the other of the mount frame and the snowplow frame having first and second receivers, the first and second receivers receiving the first and second arms, respectively, one of the mount frame and the snowplow frame having first and second latch pins, respective ones of which removably secure the first and second arms in the first and second receivers, and a lever operably associated with the first and second latch pins to simultaneously actuate the latch pins to an unlatched position, actuating the lever to simultaneously actuate the latch pins to the unlatched position and effecting relative movement between the mount frame and the snowplow frame so that the arms move out of the receivers.

Another method of detaching a snowplow frame from a mount frame comprises providing a mount frame secured to a vehicle and a snowplow frame removably attached to the mount frame, the snowplow frame including a jack stand moveable to and between an extended ground contacting and snowplow frame supporting position and a refracted ground noncontacting and snowplow frame nonsupporting position, one of the mount frame and the snowplow frame having a latch mechanism which removably secures the snowplow frame to the mount frame and a lever which actuates the latch mechanism to an unlatched position and which frees the jack stand for movement into the extended position, actuating the lever to actuate the latch mechanism to the unlatched position and to free the jack stand to drop by gravity to the extended position, and effecting relative movement between the mount frame and the snowplow frame to separate the mount frame from the snowplow frame.

The invention thus provides for the simultaneous latching and unlatching of the latch pins of a snowplow and for the automatic deployment of the snowplow jack stand during unlatching of the latch mechanism of the snowplow.

These and other features and advantages of the present invention will become more readily apparent during the following detailed description taken in conjunction with the drawings herein, in which:

BRIEF DESCRIPTION OF THE DRAWINGS OF THE INVENTION

<figref idref="DRAWINGS">FIG. 1</figref> is a side view of the snowplow and mount assembly of the present invention;

<figref idref="DRAWINGS">FIG. 2</figref> is a rear perspective view of the snowplow assembly of <figref idref="DRAWINGS">FIG. 1</figref>;

<figref idref="DRAWINGS">FIG. 3</figref> is an enlarged rear perspective view of the right hand receiver and its respective latch pin;

<figref idref="DRAWINGS">FIG. 4</figref> is an enlarged rear view of the jack stand lock which prevents relative movement of the jack stand relative to the snowplow frame when the jack stand is in the extended position, shown unlocked;

<figref idref="DRAWINGS">FIG. 5</figref> is an enlarged rear perspective view of the jack stand lock which prevents relative movement of the jack stand relative to the snowplow frame when the jack stand is in the retracted position, shown unlocked; and

<figref idref="DRAWINGS">FIG. 6</figref> is the jack stand lock of <figref idref="DRAWINGS">FIG. 5</figref>, shown locked.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

Referring first to <figref idref="DRAWINGS">FIGS. 1 and 2</figref> there is illustrated a snowplow and mount assembly <b>10</b> according to the principles of the present invention. Snowplow and mount assembly <b>10</b> comprises a snowplow assembly <b>12</b> and a mount assembly <b>14</b>. Snowplow assembly <b>12</b> can comprise a snowplow frame <b>20</b> having a lift frame <b>22</b> and an A-frame <b>24</b> pivoted to the lift frame <b>22</b>. A-frame <b>24</b> can be pivotally connected to lift frame <b>22</b> on a rearward end <b>26</b> of the A-frame <b>24</b> such as by bolt <b>28</b> for example. A forward end <b>30</b> of the A-frame <b>24</b> can carry a plow blade <b>32</b>. A-frame <b>24</b> can comprise left and right hand A-frame elements <b>34</b>, <b>36</b>, respectively, and a transverse element <b>38</b> interconnecting left and right hand A-frame elements <b>34</b>, <b>36</b>.

Lift frame <b>22</b> can comprise left and right hand upwardly extending elements <b>40</b>, <b>42</b>, respectively, interconnected at their upper ends by transversely extending element <b>44</b>. Another transversely extending element <b>46</b> can interconnect the elements <b>40</b>, <b>42</b> generally medially of the height extent of the elements <b>40</b>, <b>42</b>. Transversely extending element <b>46</b> can include top <b>48</b> and bottom <b>50</b> plates.

The lower ends of elements <b>40</b>, <b>42</b> of lift frame <b>22</b> can include receivers <b>52</b>, <b>54</b>, respectively. Left hand receiver <b>52</b> can include sidewalls <b>56</b>, <b>58</b> having outwardly flared end portions <b>60</b>, <b>62</b>, respectively. A floor <b>64</b> can interconnect the sidewalls <b>56</b>, <b>58</b>. Similarly, right hand receiver <b>54</b> can include sidewalls <b>66</b>, <b>68</b> having outwardly flared end portions <b>70</b>, <b>72</b>, respectively. A floor <b>74</b> can interconnect the sidewalls <b>66</b>, <b>68</b>.

Lift frame <b>22</b> can include a lift arm <b>80</b> pivoted to transversely extending element <b>44</b>. A lift chain <b>82</b> and spring <b>84</b> can connect the lift arm <b>80</b> to the A frame <b>24</b>. Alternatively a flexible wire rope cable can be used in place of the lift chain <b>82</b>. A lift cylinder <b>86</b> can be pivotally mounted to the lift arm <b>80</b> and transversely extending element <b>46</b> of the lift frame <b>22</b>, for raising and lowering lift arm <b>80</b> and hence A-frame <b>24</b> and plow blade <b>32</b>. Head light <b>88</b> can be mounted to transversely extending element <b>44</b>.

Referring now back to <figref idref="DRAWINGS">FIG. 1</figref>, mount assembly <b>14</b> can comprise a mount frame <b>90</b> adapted to be secured to a vehicle (phantom) having a pair of spaced arms <b>92</b>, <b>92</b>. Arms <b>92</b>, <b>92</b> are receivable in the receivers <b>52</b>, <b>54</b> of lift frame <b>22</b>. Each arm <b>92</b> includes a latch pin receiving hole <b>94</b> therein, the operation of which will be described below.

Referring now to <figref idref="DRAWINGS">FIGS. 1 through 3</figref>, a latch mechanism <b>100</b> can removably secure the snowplow frame <b>20</b> to the mount frame <b>90</b>. Latch mechanism <b>100</b> can comprise first and second latch pins <b>102</b>, <b>104</b> associated with receivers <b>52</b>, <b>54</b>, respectively. Latch pin <b>102</b> is operable to pass through hole <b>110</b> in sidewall <b>56</b>, hole <b>94</b> in arm <b>92</b> and hole <b>112</b> in sidewall <b>58</b>, when arm <b>92</b> is received within receiver <b>52</b>. Similarly, latch pin <b>104</b> is operable to pass through hole <b>120</b> in sidewall <b>68</b>, hole <b>94</b> in the other arm <b>92</b> and hole <b>122</b> in sidewall <b>66</b>, when the other arm <b>92</b> is received within receiver <b>54</b>. A bracket <b>130</b> can be mounted to the outboard side of sidewall <b>56</b> of receiver <b>52</b> to carry latch pin <b>102</b> therein. A spring <b>132</b> can bias latch pin <b>102</b> into the latched position. More particularly, a cross pin <b>134</b>, for example roll pin, can be pressed through a hole (not shown) in latch pin <b>102</b>. Spring <b>132</b> can be disposed between cross pin <b>134</b> and an inboard surface of end plate <b>136</b> of bracket <b>130</b>. Similarly, a bracket <b>140</b> can be mounted to the outboard side of sidewall <b>68</b> of receiver <b>54</b> to carry latch pin <b>104</b> therein. A spring <b>142</b> can bias latch pin <b>104</b> into the latched position. More particularly, a cross pin <b>144</b>, for example roll pin, can be pressed through a hole (not shown) in latch pin <b>104</b>. Spring <b>142</b> can be disposed between cross pin <b>144</b> and an inboard surface of end plate <b>146</b> of bracket <b>140</b>.

Referring now to <figref idref="DRAWINGS">FIGS. 2 and 3</figref>, receivers <b>52</b>, <b>54</b> can each include a pin extractor <b>150</b>, <b>152</b> associated respectively therewith. Each extractor <b>150</b>, <b>152</b> can include a cam <b>154</b>, <b>156</b>, respectively, which can be in the form of a ramp, to cam against cross pins <b>134</b>, <b>142</b>, respectively, and hence operably against latch pins <b>102</b>, <b>104</b>, respectively, the operation of which will be described below.

A latch lever <b>160</b> can be operably associated with the first and second latch pins <b>102</b>, <b>104</b> for simultaneously actuating the latch pins <b>102</b>, <b>104</b> to latched and unlatched positions. Latch lever <b>160</b> can include a connecting rod <b>162</b> extending transversely of the lift frame <b>22</b> and pivotally connected thereto. First and second linkage mechanisms <b>164</b>, <b>166</b> can be connected to latch lever <b>160</b> for actuating the extractors <b>150</b>, <b>152</b> associated with latch pins <b>102</b>, <b>104</b>, respectively. Linkage <b>164</b> can include a linkage arm <b>170</b> connected to connecting rod <b>162</b> and a linkage rod <b>172</b> pivotally connected on a first end to the linkage arm <b>170</b> and connected on a second end to the extractor <b>150</b>. Similarly, linkage <b>166</b> can include a linkage arm <b>180</b> connected to connecting rod <b>162</b> and a linkage rod <b>182</b> pivotally connected on a first end to the linkage arm <b>180</b> and connected on a second end to extractor <b>152</b>.

In use, rotation of latch lever <b>160</b> counterclockwise (as viewed from the left hand side shown in <figref idref="DRAWINGS">FIG. 1</figref>) from the up position (solid, <figref idref="DRAWINGS">FIG. 1</figref>) to the down position (phantom, <figref idref="DRAWINGS">FIG. 1</figref>), as when detaching the snowplow assembly <b>12</b> from the mount assembly <b>14</b>, actuates linkages <b>164</b>, <b>166</b> to pull extractors <b>150</b>, <b>152</b> upwardly and frontwardly. The ramped cams <b>154</b>, <b>156</b> of the extractors <b>150</b>, <b>152</b> force cross pins <b>134</b>, <b>144</b> laterally outwardly against the bias of springs <b>132</b>, <b>142</b> thus moving latch pins <b>102</b>, <b>104</b> laterally outwardly to their unlatched positions. Rotation of latch lever <b>160</b> clockwise from the down position to the up position, as when attaching the snowplow assembly <b>12</b> to the mount assembly <b>14</b>, actuates linkages <b>164</b>, <b>166</b> to push extractors <b>150</b>, <b>152</b> downwardly and rearwardly. The ramped cams <b>154</b>, <b>156</b> of the extractors <b>150</b>, <b>152</b> permit cross pins <b>134</b>, <b>144</b> to move laterally inwardly via the bias of springs <b>132</b>, <b>142</b> thus moving latch pins <b>102</b>, <b>104</b> laterally inwardly to their latched positions.

Referring now to <figref idref="DRAWINGS">FIGS. 1</figref>, <b>2</b> and <b>4</b>-<b>6</b>, a jack stand <b>190</b> can be slidably mounted to lift frame <b>22</b>. Jack stand <b>190</b> can include a leg <b>192</b> and a foot <b>194</b>. Jack stand <b>190</b> is moveable to and between an extended ground contacting and snowplow frame supporting position (solid, <figref idref="DRAWINGS">FIG. 1</figref>) and a retracted ground noncontacting and snowplow frame nonsupporting position (phantom, <figref idref="DRAWINGS">FIG. 1</figref>; <figref idref="DRAWINGS">FIG. 2</figref>). First <b>200</b> and second <b>202</b> jack stand locks can be provided to prevent relative movement of the jack stand <b>190</b> relative to the lift frame <b>22</b> when the jack stand <b>190</b> is in the extended position, and to prevent relative movement of the jack stand <b>190</b> relative to the lift frame <b>22</b> when the jack stand <b>190</b> is in the retracted position, respectively.

First jack stand lock <b>200</b> can include a lock lever <b>210</b> pivoted to a wall <b>212</b> of a bracket <b>214</b> mounted to top plate <b>48</b> of transverse element <b>46</b> of lift frame <b>22</b>. Lock lever <b>210</b> can be pivoted to wall <b>212</b> as by passing an end <b>216</b> of lever <b>210</b> through aperture <b>218</b> in wall <b>212</b>. Lock lever <b>210</b> can have an aperture <b>220</b> therein through which jack stand leg <b>192</b> passes, and a spring <b>222</b> positioned between lock lever <b>210</b> and top plate <b>48</b> biasing edges <b>224</b>, <b>226</b> of aperture <b>220</b> into contact with jack stand leg <b>192</b>. Lock lever <b>210</b> and bracket <b>214</b> are sized and configured so as to prevent inadvertent actuation thereof when snowplow assembly <b>12</b> is detached from mount assembly <b>14</b>.

Spring <b>222</b> and lock lever <b>210</b> normally prevent upward movement of jack stand leg <b>192</b> relative to lift frame <b>22</b> while at the same time freely permitting downward movement of jack stand leg <b>192</b> relative to the lift frame <b>22</b>. Pivoting lock lever <b>210</b> downwardly (<figref idref="DRAWINGS">FIG. 4</figref>) frees jack stand leg <b>192</b> of edges <b>224</b>, <b>226</b> of lock lever aperture <b>220</b> thereby permitting upward movement of the jack stand leg <b>192</b> relative to the lift frame <b>22</b>.

Second jack stand lock <b>202</b> can include a lock pin <b>240</b> moveable into and out of an aperture <b>242</b> in jack stand leg <b>192</b> and a spring <b>244</b> biasing lock pin <b>240</b> toward the jack stand leg <b>192</b>. The spring <b>244</b> and lock pin <b>240</b> normally prevent downward movement of the jack stand <b>192</b> relative to the lift frame <b>22</b>, whereas urging the lock pin <b>240</b> against the bias of the spring <b>244</b> frees the jack stand leg <b>192</b> from the pin <b>240</b> permitting downward movement of the jack stand <b>190</b> relative to the lift frame <b>22</b>. The jack stand <b>190</b> can drop by gravity to the extended position when the jack stand leg <b>192</b> is freed from pin <b>240</b>.

The second jack stand lock <b>202</b> can further include a cam <b>260</b> connected to connecting rod <b>162</b> and a cam follower <b>262</b> having fixed thereto the lock pin <b>240</b>. Cam <b>260</b> can be in the form of a cylinder encircling connecting rod <b>162</b> and fixed thereto and cam follower <b>262</b> can be in the form of a cylinder encircling connecting rod <b>162</b> and slidable relative thereto. Cam <b>260</b> and cam follower <b>262</b> can have mating arcuate, for example helix, cam surfaces <b>264</b>, <b>266</b>, respectively. Cam follower <b>262</b> and hence lock pin <b>240</b> can be spring biased toward jack stand leg <b>192</b> via spring <b>244</b> positioned between cam follower <b>262</b> and a plate <b>272</b> connected between plates <b>48</b> and <b>50</b>. Cam follower <b>262</b> and hence pin <b>240</b> can be prevented from rotating via U-bracket <b>274</b> fixed to plate <b>50</b> and having arms <b>276</b>, <b>276</b> with holes <b>278</b>, <b>278</b> therein through which pin <b>240</b> passes.

As illustrated cam <b>260</b> is fixedly secured to connecting rod <b>162</b> and as such will rotate with connecting rod <b>162</b> as latch lever <b>160</b> is rotated. Thus, in use, rotation of latch lever <b>160</b> counterclockwise (as viewed from the left hand side shown in <figref idref="DRAWINGS">FIG. 1</figref>) from the up position (solid, <figref idref="DRAWINGS">FIG. 1</figref>) to the down position (phantom, <figref idref="DRAWINGS">FIG. 1</figref>), as when detaching the snowplow assembly <b>12</b> from the mount assembly <b>14</b>, not only actuates linkages <b>164</b>, <b>166</b> to unlatch latch pins <b>102</b>, <b>104</b> but also actuates cam <b>260</b> to unlock pin <b>240</b>. The spring rates of springs <b>132</b>, <b>142</b>, <b>222</b> and <b>244</b>, and the geometries of their associated mechanisms, can be selected so that jack stand <b>190</b> falls by gravity to the ground during the first portion of the arc traversed by lever <b>160</b> in moving lever <b>160</b> from the up position toward the down position, while latch pins <b>102</b>, <b>104</b> remain latched. Then, as lever <b>160</b> is moved the remaining portion of the arc to the down position, latch pins <b>102</b>, <b>104</b> are moved to their unlatched positions.

As described above rotation of latch lever <b>160</b> clockwise from the down position to the up position, as when attaching snowplow assembly <b>12</b> to mount assembly <b>14</b>, actuates linkages <b>164</b>, <b>166</b> to move latch pins <b>102</b>, <b>104</b> to their latched positions. Once so latched, jack stand lock lever <b>210</b> can be pressed downwardly freeing jack stand leg <b>192</b>. Jack stand leg <b>192</b> is then manually pulled upwardly until jack stand lock pin <b>240</b> is seated in aperture <b>242</b> in jack stand leg <b>192</b>.

For both attaching the snowplow assembly <b>12</b> to and detaching the snowplow assembly <b>12</b> from the mount assembly <b>14</b> a force should be applied to the lift frame <b>22</b>, such as on transverse element <b>44</b>, in the direction of the mount assembly <b>14</b> as latch lever <b>160</b> is rotated. Such movement facilitates alignment of the latch pins <b>102</b>, <b>104</b> with the holes <b>94</b> in the arms <b>92</b>. This movement is possible because tension spring <b>84</b>, extended during normal operation of snowplow assembly <b>12</b>, retracts when snowplow assembly <b>12</b> is parked, blade <b>32</b> is dropped to the ground and the hydraulic control is placed in the “float” condition releasing the pressure in the lift cylinder <b>86</b>, pulling lift arm <b>80</b> downwardly to its fully collapsed positioned and creating slack in the lift chain <b>82</b>.

Latch lever <b>160</b> and linkage mechanisms <b>164</b>, <b>166</b> are designed so that the mechanical advantage produced thereby is insufficient to unlatch “loaded” latch pins <b>102</b>, <b>104</b>, thus preventing the snowplow assembly <b>12</b> from “collapsing in a heap.” In other words, and as discussed above, initial rotation of latch lever <b>160</b> permits jack stand <b>190</b> to fall by gravity and support the snowplow assembly <b>12</b>. Further rotation of latch lever <b>160</b> to retract latch pins <b>102</b>, <b>104</b> is not possible until lift frame <b>22</b> is pivoted relative to A-frame <b>24</b> and toward mount frame <b>90</b> to unload latch pins <b>102</b>, <b>104</b>. Jack stand <b>190</b> and jack stand foot <b>194</b> are sized, configured and located to permit such pivoting of lift frame <b>22</b> relative to A-frame <b>24</b> without causing instability of the snowplow assembly <b>12</b> during such pivoting.

Those skilled in the art will readily recognize numerous adaptations and modifications which can be made to the present invention which will result in an improved snowplow and mount assembly, yet all of which will fall within the spirit and scope of the present invention as defined in the following claims. Accordingly, the invention is to be limited only by the scope of the following claims and their equivalents.